Air filter with balanced seal

ABSTRACT

An air filter and dust collector are provided. In one embodiment, the air filter includes a filter element coupled at a first end to a end cap and at a second end to a first side of a rectangular filter flange assembly. The rectangular filter flange assembly includes a central aperture open to an interior region bounded by the filter element. A rectangular gasket is disposed on the second side of the filter flange assembly and circumscribes the central aperture.

BACKGROUND

1. Field

The present invention relates to an air filter having a balanced sealand a dust collector for use with same.

2. Description of the Related Art

In many dust collecting systems, an air filter with a rectangular flangeis employed. The rectangular flange extends beyond the periphery of theair filter and provides a surface for mounting the air filter to thedust collector. The air filter is mounted to the dust collector byclamping the air filter to a tube sheet disposed in the dust collectorwhich separates dirty and clean air plenums. Dirty air entering thedirty air plenum of the dust collector passes through the air filter toremove particulate entrained in the dirty air. The filtered air exitsthe air filter and passes through a hole in the tube sheet into theclean air plenum, from which the filtered clean air is exhausted toatmosphere from the dust collector. The air filter is sealed to the tubesheet by means of a clamp which engages the flange of the air filter. Inmany systems, the clamping mechanism comprises two parallel clampingbars which may be actuated toward the tube sheet, thereby engaging theflange and compressing a gasket mounted to the flange against the tubesheet, thereby creating a seal between the air filter and the tubesheet. To provide good engagement between the clamping mechanism and theflange of the air filter, the flange is typically square or rectangular.

FIG. 1 illustrates a top perspective view of a conventional air filter100. The air filter 100 includes a cylindrical filter element 110bounded by an end cap 106 at a first end and a rectangular flange 104 ata second end. The rectangular flange 104 is shown in FIG. 1 as havingtwo short edges 112 and two long edges 114. The rectangular flange 104includes an aperture 120 to allow air passing through the filter element110 to exit the filter 100 and a ring shaped recessed channel 130 forreceiving the filter element 110.

At least one circular gasket 108 is coupled to the rectangular flange104 generally on the backside of the recessed channel 130, which islocated well inward of the perimeter of the rectangular flange 104. Thegasket 108 closely circumscribes the aperture 120 to seal the filter 100against a mounting surface (not shown FIG. 1). The circular gasket 108is laterally well spaced from an edge 112 of the flange 104; generallydirectly above the filter element 110 potted in the recessed channel130.

The filter 100 is conventionally secured to the mounting surfaceapplying a force to an area 116 located immediately along the long edges114 of the flange 104. In FIG. 1, the area 116 extends about 1-2 inchesinward from the long edges 114 of the flange 104, as shown by imaginarydashed lines 122. As a result, as the clamping mechanism engages thearea 116 of the flange 104 along the long edges 114, the clamping forcemust be transferred laterally through the flange 104 to the gasket 108.As a result, the gasket 108 is loaded non-uniformly which may contributeto potential leakage. For example, a region 118 of the gasket 108closest to the short edges 112 has less loading then a region 124 of thegasket closest to the long edges 114. Additionally, the offset betweenthe area 116 that clamping force is applied to the location when thegasket 108 is loaded may cause the flange 104 to further deflect alongthe short edges 112, further contributing to non-uniformity of thesealing force applied to the gasket 108 and further increasing thepotential for air bypassing the filter 100.

Therefore, there is a need for an improved air filter with a balanceseal which improves the uniformity of the clamping force.

SUMMARY

An air filter and dust collector are provided. In one embodiment, theair filter includes a filter element coupled at a first end to a end capand at a second end to a first side of a rectangular filter flangeassembly. The rectangular filter flange assembly includes a centralaperture open to an interior region bounded by the filter element. Arectangular gasket is disposed on the second side of the filter flangeassembly and circumscribes the central aperture.

In another embodiment, a dust collector includes a housing having aninlet, an outlet, and a filter access port sealable by a door. A tubesheet is disposed within the housing. The tube sheet separates a dirtyair plenum from a clean air plenum within the housing. The tube sheethas at least one rectangular filter aperture formed therethroughallowing fluid communication between the dirty air plenum and the cleanair plenum. A mounting mechanism is disposed in the housing and isoperable to clamp a filter flange assembly of an air filter to the tubesheet such that the outlet of the air filter aligns with the rectangularfilter aperture.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 is a top perspective view of a conventional air filter known inthe art;

FIG. 2 is a partial cut away elevation of one embodiment of a dustcollector having at least one air filter disposed therein;

FIG. 3 is a top perspective view of one embodiment of the air filter ofFIG. 2;

FIG. 4 is a top view of the air filter of FIG. 2;

FIG. 5A is cross-sectional view of the air filter of FIG. 2 taken alongsection line 5-5 of FIG. 4;

FIG. 5B is a cross-sectional view of one embodiment of the air filter ofFIG. 2 taken along section line 5-5 of FIG. 4;

FIG. 6 is a partial cross-sectional view of the dust collector of FIG. 2detailing the air filter sealing interface;

FIG. 7 is a partial sectional view of the dust collector of FIG. 2 takenalong section line 7-7 of FIG. 2; and

FIG. 8 is front sectional view of another embodiment of an air filter.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

FIG. 2 is a partial cut away elevation of one embodiment of a dustcollector 200 having at least one replaceable air filter 216. Althoughthe replaceable air filter 216 is illustrated used in an exemplaryembodiment of the dust collector 200, it is contemplated that allembodiments of the air filters described herein may be utilized in dustcollectors of varying designs from different manufactures.

The dust collector 200 includes a housing 204 that is coupled to an airmover 210, such as a fan or blower, for drawing air through the at leastone replaceable air filter 216 mounted in the housing 204. The air mover210 may be mounted to or be remote from the housing 204. The housing 204is constructed from a rigid material suitable to withstand theoperational pressures and loading for which the particular dustcollector is designed. The housing 204 includes an inlet 230, an outlet232 and a filter access port 234 (partially shown in phantom) sealableby a filter access door 236. The filter access door 236 may be opened toreplace the at least one replaceable air filter 216 disposed in thehousing 204 and closed to sealingly isolate the interior of the housingfrom the surrounding environment. The housing 204 is supported by legs202 and includes a tube sheet 218 which separates the interior of thehousing 204 into a dirty air plenum 206 and a clean air plenum 208. Thedirty air plenum 206 is in communication with the inlet 230 of thehousing 204 while the clean air plenum 208 is in communication with theoutlet 232 of the housing 204. The at least one air filter 216 issealingly mounted to the tube sheet 218 such that air moving passingthrough a filter aperture 240 formed through the tube sheet 218 from thedirty air plenum 206 to the clean air plenum 208 must first pass throughthe at least one air filter 216. The filter aperture 240 may have anysuitable geometry, and preferably is rectangular as shown in thesectional view of the dust collector 200 shown in FIG. 7 to allowgreater tolerance for misalignment between a centerline 270 of the airfilter 216 and a centerline 272 of the filter aperture 240. Thecenterline 270 of the air filter 216 and the centerline 272 of thefilter aperture 240 are shown in co-linear alignment in FIG. 2. Thegreater tolerance for misalignment between the air filter 216 and thefilter aperture 240 advantageously minimizes the probability of the airfilter 216 blocking a portion of the filter aperture 240 which wouldresult in higher operational pressure and undesirable increase in energyconsumption.

Not shown in FIG. 2, the dust collector 200 may optionally includes afilter cleaning system which is operable to remove at least a portion ofthe dust cake formed on the air filter during operation. The filtercleaning system may vibrate, shock or utilized air jets to knock atleast a portion of the dust cake formed on the air filter into acollection hopper 242 formed in the lower portion of the housing 204.The collection hopper 242 includes a door 244 which may be periodicallyopened to remove the dust or other filtered materials from the dustcollector 200.

Each air filter 216 is sealingly mounted to the tube sheet 218 by amounting mechanism 260. Many different types of mounting mechanism 260are commonly known in the art, any of which may be employed in thehousing 204. In the exemplary embodiment depicted in FIG. 2, themounting mechanism 260 includes a pair of bars 262 coupled by actuators264 to one of the housing 204 or tube sheet 218. The actuators 264 areoperable to move the bars 262 selectively towards and away from the tubesheet 218. When the bars 262 are moved to a closed position towards thetube sheet 218, the air filter 216 is sealingly pushed against the tubesheet 218. When the bars 262 are moved to an open position away from thetube sheet 218, the air filter 216 is spaced from the tube sheet 218thereby allowing removal of the air filter 216 through the filter accessport 234.

In the embodiment depicted in FIG. 2, the actuator 264 of the mountingmechanism 260 includes a cam member 266 and a lever 268. The lever 268may be actuated, for example, by motor, cylinder, by hand or othersuitable means, between a first portion which rotates the cam member 266to an orientation that displaces the bar 262 towards the tube sheet 218(i.e., the closed position) and a second portion which rotates the cammember 266 to an orientation that displaces the bar 262 away from thetube sheet 218 (i.e., the open position). In the illustration of thedust collector 200 depicted in FIG. 2, the mounting mechanism 260 on theleft side of the housing 204 is shown in the closed position clampingthe air filter 216 against the tube sheet 218 while the mountingmechanism 260 on the right side of the housing 204 is shown in the openposition spacing the bar 262 from the tube sheet 218 to facilitateloading a replacement air filter 216 (shown in phantom on the right handside).

FIGS. 3, 4, and 5A are top perspective, top and cross-sectional views ofone embodiment of the air filter 216. The air filter 216 includes atubular filter element 302, an end cap 300 and a filter flange assembly310. The filter flange assembly 310 includes a top surface 352 and abottom surface 354, defining the upper-most and lower-most surfaces ofthe filter flange assembly 310. The filter flange assembly 310 alsoincludes at least one perimeter gasket 308. The top and bottom surfaces352, 354 may be part of a one piece unitary component of a filter flangeassembly as illustrated by flange 502 of a filter flange assembly 550illustrated in FIG. 5B, or as a multi-piece component of the filterflange assembly 310, as shown in FIG. 5A. In the embodiment depicted inFIG. 5A, the filter flange assembly 310 comprises of a second flange 340and a first flange 342. The second flange 340 may include a recessedchannel 350, a second flange aperture 344, a top surface 360, and abottom surface 362, wherein the bottom surface 362 of the second flange340 defines the bottom surface 354 of the filter flange assembly 310.The first flange 342 include an inner lip 358, a first flange aperture346, an outer lip 348, a bottom surface 364, and a top surface 366,wherein the top surface of the first flange 342 defines the top surface352 of the filter flange assembly 310. The outer lip 348 of the firstflange 342 is radially well outward of the recessed channel 350 of thesecond flange 340, and adjacent, i.e., near, the perimeter of the secondflange 340.

The first and second flanges 342, 340 may be coupled together by anysuitable method, for example welding, bonding, fastening orpress-fitting, among other joining methods. In the embodiment depictedin FIG. 3, the flanges 340, 342 are press-fit together. For example, theinner lip 358 extends from the bottom surface 364 of the first flange342 and is press-fit into the second flange aperture 344 of the secondflange 342. The outer lip 348 extending from the bottom surface 364 ofthe first flange 342 abuts the top surface 360 of the second flange 340,thus maintaining the top surface 352 and bottom surface 354 of thefilter flange assembly 310 in a spaced apart relation “X” between about⅜ inches to ⅝ inches, for example ½ inches. The spaced apartrelationship X of the top and bottom surfaces 352, 354 advantageouslyallows a shorter gasket 308 to be utilized. Tall, e.g. high aspectratio, gaskets are difficult to form and provide unreliable seals. Thus,the spaced apart relation X of the top and bottom surfaces 352, 354allows the height of the gasket 308 to be maintained at conventionalaspect ratios having proven reliability. Moreover, since the top surface352 defined by the top surface 366 of the first flange 340 extends wellbeyond the area above the recessed channel 350, the gasket 308 may bepositioned well outward of the recessed channel 350 and filter element302 to provide a more balanced seal as further described below.

The filter flange assembly 310 may have a rectangular outer edge 334,although other geometries may be utilized. The rectangular outer edge334 facilitates use of multiple air filters 216 arranged in an array tobe located accurately within the duct collector 200 with minimal effortor hardware. As illustrated in the top view of the air filter 216depicted in FIG. 3, the rectangular outer edge 334 of the filter flangeassembly 310 includes long edges 320 adjacent to short edges 322. Thegasket 308 is immediately adjacent the long edges 320. The outer edge334 may also include an outer lip 324 extending out of the plane of thefilter flange assembly 310 away from the tubular filter element 302 toincrease the rigidity of the filter flange assembly 310. It iscontemplated that the outer lip 324 of the second flange 340 may besecured to the outer lip 348 of the first flange 342.

The tubular filter element 302 may be formed from pleated filter mediaselected to provide the pressure drop and efficiency desired for thedesigned operating parameters of the dust collector 200. The filtermedia may be woven or non-woven filtration material, including wet-laid,meltblown, air-laid, needled, and composite filter media, among others.Filter media suitable for fabricating the tubular filter element 302 iswell known and widely available, for example, from suppliers such asHollingsworth & Vose Company, Lydall, Inc., and the like.

The end cap 300 is generally a disk to which one open end of the tubularfilter element 302 is secured by an adhesive. Adhesives suitable for thetubular filter element 302 to the end cap 300 include polyurethanes andsilicone adhesives. In one embodiment, the tubular filter element 302 ispotted to the end cap 300 to prevent air from leaking therebetween.

The other open end of the tubular filter element 302 is secured in therecessed channel 350 formed in the bottom surface 354 of the filterflange assembly 310 also by an adhesive. The same adhesives may be usedfor securing the tubular filter element 302 to the filter flangeassembly 310 as described above. In one embodiment, the tubular filterelement 302 is potted to the filter flange assembly 310 to prevent airfrom leaking therebetween.

The filter flange assembly 310 also includes a central aperture 312. Inthe embodiment depicted in FIG. 5A, the inside diameter of the inner lip358 defines the central aperture 312. The central aperture 312 is opento an interior region 314 of the air filter 216 bounded by the tubularfilter element 302. Thus, air passing through the tubular filter element302 into the interior region 314 is directed out of the air filter 216through the central aperture 312 formed in the filter flange assembly310. The central aperture 312 generally is circular in geometry, and ofsufficient diameter as to not add pressure drop of air passing throughthe air filter 216 at designed air flow rates, which are typicallyaround 100 feet per second of face velocity.

The at least one perimeter gasket 308 is secured to the top surface 352of the filter flange assembly 310 to seal against the tube sheet 218during use. The gasket 308 may be an elastomeric material, such assilicone, neoprene, butyl, nitrile, ethylene propylene and the like. Thegasket 308 may be affixed to the second side 332 of the filter flangeassembly 310 by a pressure sensitive adhesive or, alternatively, pouredin place.

The perimeter gasket 308 located very close to an outer edge 334 of thefilter flange assembly 310 and circumscribes the central aperture 312.In one embodiment, the gasket 308 has a height between about ½ inches to¾ inches, for example ⅝ inches. As illustrated in the embodimentdepicted in FIG. 3, the perimeter gasket 308 is disposed substantiallyequidistant from both the short and long edges 322, 320 of the filterflange assembly 310. In one embodiment, two or more perimeter gaskets308 may be utilized, such as an inner and outer perimeter gasketsidentified by reference numerals 304, 306.

The perimeter position of the gasket 308 is enabled by the radialexpanse of the top surface 352, which in the embodiments is depicted inboth FIGS. 5A-5B, and is created by the top surface 352 not beingconfined to only the region directly above the recessed channel found inconventional designs fabricated using single element sheet metalflanges. For example, since the perimeter of the first flange 342extends well beyond to radial bounds of the recessed channel 350 to alocation very close to the outer edge 334 of the filter flange assembly310, the gasket may be positioned very close to the outer edge 334. Thebenefits of this perimeter location of the gasket 308 are best describedwith reference to FIG. 6 below.

FIG. 6 is a partial cross-sectional view of the dust collector of FIG. 2detailing the air filter sealing interface between the tube sheet 218and the filter flange assembly 310. As the perimeter gasket 308 islocated along the entire long edge 320 of the filter flange assembly 310and in an area 604 of filter flange assembly 310 in which the bar 262 ofthe mounting mechanism 260 contacts the filter flange assembly 310, theforce urging the filter flange assembly 310 towards against the tubesheet 218 applied by the actuator 264 is linearly aligned with thegasket 308 (i.e., the bar 262, gasket 308 and tube sheet 218 arelinearly co-aligned with the motion of the bar 262, as illustrated byarrows 602) thereby applying a uniform compression force to a portion370 of the gasket 308 aligned with the long edge 320 without generatinga cantilever force on the filter flange assembly 310 which could reducethe force applied to a portion 372 of the gasket 308 aligned with theshort edge 322 of the filter flange assembly 310. The substantialelimination of the cantilever force on the filter flange assembly 310substantially decreases the variance in the compression force to theportion 372 of the gasket 308 aligned with the short edge 322 of thefilter flange assembly 310 because the filter flange assembly 310 ismuch less likely to deflect as compared to conventional designs, therebyresulting in a much more robust and reliable air filter 216 to tubesheet 218 seal. Additionally, as the sealing forces is more uniformlydistributed on the gasket 308, less sealing force is needed, therebyallowing for lighter and less expensive mounting mechanisms 260. As anadditional benefit, the location of the gasket 308 uniformly adjacentthe outer edge 334 of the filter flange assembly 310 reduces the area ofthe second side 332 the filter flange assembly 310 exposed to the dirtyair plenum 206, thereby reducing the amount of dust or other particulatematter which can collect on the second side 332 the filter flangeassembly 310 during use which creates a mess during filter exchange.

FIG. 8 is a front perspective view of another embodiment of an airfilter 800 with may be utilized with the dust collector 200, amongothers. The air filter 800 is similar to the air filter 216 describedabove, having a filter flange assembly 310 and gasket 308 that providethe beneficial sealing attributes, except in that the air filter 800includes a bag filter element 802 instead of a tubular filter element302.

Thus, an air filter having a rectangular perimeter gasket uniformlyfollowing an edge of the filter flange has been provided that providesuniform and balanced sealing forces. The uniform and balanced sealingforces improve sealing between the air filter and dust collector,thereby improving the performance of a dust collector utilizing suchfilters. Additionally, a dust collector is provided that has increasedtolerance for mismatched alignment between the air filter and dustcollector, thereby making the dust collector less susceptible toincreased pressure lose and power consumption due to filtermisalignment.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. An air filter, comprising: an end cap; a filterelement coupled at a first end to the end cap; a rectangular filterflange assembly having a bottom surface coupled to a second end of thefilter element, the rectangular filter flange assembly having a centralaperture open to an interior region bounded by the filter element; and agasket disposed on a top surface of the filter flange assembly radiallyoutward of the filter element and circumscribing the central aperture.2. The air filter of claim 1, wherein the rectangular filter flangeassembly comprises: a pair of short edges and a pair of long edges,wherein the gasket is immediately adjacent the long edges.
 3. The airfilter of claim 1, wherein the gasket is rectangular.
 4. The air filterof claim 1, wherein the filter element is cylindrical.
 5. The air filterof claim 1, wherein the filter element is a bag.
 6. The air filter ofclaim 1, wherein the rectangular filter flange assembly comprises: arecessed channel formed in the bottom surface and receiving the filterelement.
 7. The air filter of claim 6, wherein the rectangular filterflange assembly comprises: a first flange having the gasket mountedthereto; and a second flange having the recessed channel formed therein.8. The air filter of claim 7, wherein the first flange is press-fit tothe second flange.
 9. The air filter of claim 1, wherein the top surfaceis spaced from the bottom surface of the filter flange assembly by atleast ⅜ inches.
 10. A dust collector comprising: a housing having aninlet, an outlet, and a filter access port sealable by a door; a tubesheet separating a dirty air plenum from a clean air plenum within thehousing, the tube sheet having at least one rectangular filter aperture;a mounting mechanism disposed in the housing an operable to clamp afilter flange assembly of an air filter to the tube sheet such that theoutlet of the air filter aligns with the rectangular filter aperture.11. The dust collector of claim 10, wherein the mounting mechanismcomprises: a pair of bars disposed on either side of the at least onerectangular filter aperture; and an actuator coupled to each bar. 12.The dust collector of claim 11, wherein the actuator of the mountingmechanism comprises: a lever; and a cam member coupled to the lever andthe bar.
 13. The dust collector of claim 10, wherein the at least onerectangular filter aperture of the tube sheet comprises: an array ofrectangular filter apertures, wherein at least two rectangular filterapertures are associated with each mounting mechanism.
 14. The dustcollector of claim 11, wherein the at least one rectangular filteraperture of the tube sheet comprises: an array of rectangular filterapertures, wherein at least two rectangular filter apertures aredisposed between each pair of bars.
 15. The dust collector of claim 10further comprising: at least one air filter comprising: an end cap; afilter element coupled at a first end to the end cap; a rectangularfilter flange assembly having a bottom surface coupled to a second endof the filter element, the rectangular filter flange assembly having acentral aperture open to an interior region bounded by the filterelement; and a gasket disposed on a top surface of the filter flangeassembly radially outward of the filter element and circumscribing thecentral aperture.
 16. The dust collector of claim 15, wherein the atleast one air filter further comprises: a recessed channel formed in thebottom surface and receiving the filter element; a first flange havingthe gasket mounted thereto; and a second flange having the recessedchannel formed therein.
 17. The dust collector of claim 15, wherein thegasket is rectangular.
 18. The dust collector of claim 17, wherein thetwo sides of the gasket are directly between the tube sheet and a pairof bars disposed on either side of the at least one rectangular filteraperture.
 19. The dust collector of claim 18, wherein the filter elementis cylindrical.
 20. The dust collector of claim 18, wherein the filterelement is a bag.